76 patten: [Vol. I. 



which terminate at the edge of the cornea in an outward curve 

 as though attached to the epithelium at that point, forming 

 what I have called the ciliaris; other fibres are continued onward 

 between the cornea and lens, forming an almost structureless 

 layer, the pseudo-corjiea, in which nuclei are seldom seen. 



The lens is held in place by a suspensory ligament attached to 

 the periphery of its outer surface, which is supplied with a layer 

 of concentric, circular fibres superimposed by a layer of radi- 

 ating ones. 



The inner surface of the lens is sparingly supplied with 

 branching fibres, which, in Pccten operczdaris, accumulate near 

 the centre to form a nucleated mass of fibres connecting the 

 lens with the septal membrane. 



In Pecten operciilaris there is a special accumulation of cir- 

 cular fibres to form two contractile rings, situated close together, 

 one on the outer and the other on the lateral surface of the 

 lens. The inner surface of the lens is much more convex than 

 the outer. 



The posterior portion of the eye consists of a concave disc, 

 completely enclosed within a membranous sac. The thick ante- 

 rior wall of the sac, or the septal membrane, serves to protect the 

 retinal cells, and as an elastic cushion for the lens. The inner 

 wall constitutes a tough, double-layered sclerotica. At the con- 

 fluence of these two membranes the wall of the sac is much thin- 

 ner, and is perforated by innumerable passages for the entrance 

 of nerve-fibres from the axial branch of the optic nerve. The 

 cells within the ommateal sac constitute a closed vesicle whose 

 anterior and posterior walls touch each other, "thus obliterating 

 the central cavity. The wall of the vesicle was originally com- 

 posed of a single layer of cells, an arrangement which is subse- 

 quently obscured by the division of both anterior and posterior 

 walls into several secondary layers. The posterior wall of the 

 ommateal vesicle consists of four layers, — the vitreous tiet-work, 

 the double-layered argentea, and the tapetian. The anterior 

 wall is likewise composed of four layers, — an outer ganglionic 

 layer, an inner ganglionic layer, the retinophorcs, and the rods. 



The retinophorcB (Fig. 15) are long, bent cells, one end sup- 

 plied with an inwardly directed rod, while the other is drawn out 

 to a slender tube continuous with the axial nerve. Each retino- 

 phora contains a large, oval nucleus and a small, faintly stain- 



